Coating compositions and methods of preparing same



United States PatentO COATING COMPOSITIONS AND METHODS OF PREPARING SAME Ralph Marotta, Malden, and Carl R. Martinson, Everett, Mass., assignors to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing. Application September 30, 1950, Serial No. 187,818

17 Claims. (Cl. 106-428) The present invention relates to improved fiatted and semi-gloss coating compositions, particularly drying oil varnishes, and also to methods of preparing suchvcompositions.

It has been proposed heretofore .to use silica aerogels or silica gels in various coating compositions for the purpose of providing a composition which when applied to substrates produces a clear and transparent flatted coating or a coating having a considerably reduced gloss or shine. Such compositions and coatings are generally referred to as fiatted or semi-gloss compositions and coatings. When silica aerogels and gels are introduced into various coating compositions, and particularly drying oil varnishes, however, theyare subject to hard settling, that is, they tend to settle out of such compositions or varnishes-to form a hard, gummy cake which is extremely difficult to disperse by ordinary stirring.

In accordance with the methods described herein, it is possible to produce flatted coating compositions and particularly drying oil varnishes containing silica aerogels or gels which are relatively free of the tendency to settle to form hard gummy cakes. Although the flatting agents in the compositions described herein may settle, they flocculate to form a voluminous relatively soft deposit which can be dispersed throughout the coating vehicle by simple stirring.

It is, accordingly, one object of this invention to provide an improved method for the prevention of hard settling of flatted coating compositions and particularly drying oil varnishes.

It is a further object of this invention to provide an improved method of flatting coating compositions and particularly drying oil varnishes Withsilica aerogels and to eliminate the formation of hard, gummycakes of such aerogels in the coating vehicle.

It is a further object of this invention to provide flatted coating compositions and particularly drying oil varnishes which are substantially free of the tendency to form hard, gummy cakes of the flatting agent.

It is a further object of this invention to provide flatted coating compositions and particularly drying oil varnishes containing silica aerogels as the fiatting agent and which are substantially free of the tendency of forming hard, gummy cakes of the aerogel.

Still further .objects and advantages of this invention will appear in the following description and the appended claims.

The compositions of this invention comprise, in general, a film-forming material in an organic solvent or other dispersing liquid, for example, a coating composition such as a lacquer or a drying oil varnish, in which is incorporated a finely divided fiatting agent comprising essentially silica such asfinely divided silica aerogel in an amount suflicient to at least reduce the gloss of coatings prepared from such lacquer or varnish and a nonionic surface active agent in an amount sutficient to substantially prevent hard caking of such flatting agent.

r r p Z ,7 1 7,2 14 Ce Patented Sept. -6, 1955 Such non-ionic surface active agent should be at least slightly solublein the coating vehicle. The compositions may also compriseother ingredients such as siccatives or driers, compatible thinners, natural or synthetic resins and small amounts say'up to 15% by weight of insoluble phthalic anhydride-glyceride resins and the like.

Other coating compositions which are useful in preparing the compositions of this invention include the lacquer type of coating materials such as the cellulose acetate-acetone lacquers, maleic rosin lacquers, nitrocellulose lacquers, polyvinyl chloride and vinyl chloridevinyl acetate copolymer lacquers and polymethyl methacrylate lacquers. Natural resin'lacquers such as copal and shellac lacquers may also'be used. Since the 'prob lem of hard settling ofsilica aerogels and gels is particularly troublesome in the case of drying oil varnishesor drying oil lacquers, the present'invention is particularly directed to overcoming this problem and accordingly the preferredcoatingcompositions for use in preparing the compositions of this invention are the drying oil type of composition and particularly the drying oil varnishes.

The silica fiatting agents used in the compositions, of

; this invention comprise essentially silica materials which are prepared by chemical reaction and are hydrophilic although insoluble in water. Included in this class of materials are the silica gels which are prepared by reacting an alkali silicate and an acid, silica aerogels Which-are prepared by removing the liquid phase from a silica'hydrogel or silica organogel, or a silica organogel which is prepared, for example, by replacing'the water in a silica hydrogel with an organic liquid. 9

Of the various possible flatting agents which may ,be used, the silica aerogels are preferred because of their high flatting efliciency, lack of migration, the clarity and transparency of the coatings containingthe same'and the fact that the silica aerogels do not appreciably impairfilm strength and, in most instances, actually improve the hardness and mar resistance of the varnish film. While such aerogels have been usedheretofore in coating compositions generally, and to some extent in drying oil varnishes specifically, they, more than any other type of known 'flatting agent, have been most susceptible to hard settling in drying oil varnish vehicles. Accordingly, because of their excellent fiatting properties and the fact that they can be usedin drying oil varnishes in combination with the non-ionic surface active agents without hard settling, they are particularly useful as flattingagents in the drying oil varnishes described herein.

The term .silica aerogel as used herein is intended to includethe materials prepared by removing a liquid from a silica gel structure without appreciable shrinkage of the gel and replacing such liquid with a gas, as, for example, air. Theseaerogels are suitably prepared, for example, by first reacting aqueous sodium silicate such as sodium silicate with an acid such as'sulfuric acid to form a silica hydrogel. This gel is then washed with Water to remove Water-soluble reactants and salts. Such gel contains Water as a liquid, phase, and this water ispreferably at least partially or completely removed from the gel before the gel is converted to an aerogel, and is replaced by a watermiscible liquid having a lower critical temperature. This is accomplished, for example, by washing the silica hydrogel with ethanol, isopropanol, acetone and the like until a substantial quantity of the water in the hydrogel has been displaced by the water-miscible liquid. The gel is then slowly heated in an autoclave or other pressure resistant vessel, small quantities of vapor being released as required to avoid excessive pressures, until the temperature of the gel is slightly above the critical temperature of the liquid in the gel. At this point the liquid has been converted to the vapor state and is slowly released as a vapor so as to avoid destruction of the gel structure. The aerogel obtained in this manner has substantially the same volume as the initial silica hydrogel and consists essentially of a cellular silica structure having a large amount of void space. A more detailed description of the above procedure for preparing aerogels will be found in the patents to Samuel S. Kistler, Nos. 2,093,454, 2,188,007 and 2,249,767.

Silica aerogels may also be prepared by heating silica organo-aquasols in an autoclave above the critical temperature of the liquid phase in essentially the same manner as described above. A detailed description of the procedure for preparing such silica organo-aquasols will be found in the Morris D. Marshall patent, No. 2,285,449.

Silica-organic liquid gels may be used instead of the silica aerogels or to replace a portion of the silica aerogels with equally good results. Such gels include those substances which are prepared by first reacting, for example, an aqueous sodium silicate and an acid, washing the resulting gel free of electrolytes and then replacing the water in the gel with an organic liquid which is miscible with the liquid constituents in the coating composition. This may be accomplished, for example, by replacing the water in the gel with an organic liquid which is miscible with water and also with the liquid constituents in the coating composition or by replacing the water in the gel with a water-miscible organic liquid and then replacing such organic liquid with another organic liquid miscible therewith and with the liquids in the coating composition. A more detailed description of the preparation of silica gels of this type will be found in the patents to Samuel S. Kistler, No. 2,188,007 and Charles G. Harford, No. 2,180,145. It is to be understood, however, that these gels are to be distinguished from ordinary silica gels, that is, gels which have been prepared, for example, by reacting an aqueous sodium silicate with an acid, washing the gel to, remove salts and then drying the gel to remove the liquid phase. This latter type of silica gel, that is, an ordinary silica gel, may be used for flatting varnishes, but is not as suitable, particularly from the standpoint of film clarity and film strength, as the silica-organic liquid gels referred to above.

The flatting agents employed in the compositions of this invention are to be distinguished from organic or inorganic pigments or soluble dyes. The organic or inorganic pigments have the property of coloring the varnish film and the term color is intended to include white and black, whereas the flatting agents employed herein are not coloring materials, that is, they do not appreciably change the original color of the varnish film. Moreover, small quantities of the pigments tend to opacify the film, that is, they render the film less clear and less transparent whereas the flatting agents employed herein do not appreciably change the clarity or transparency of the film when used in small amounts, say up to on the weight of the varnish solids. The silica flatting agents are also distinguished from most pigments in that they have a considerably larger surface area than pigments and consist of average particles which are considerably larger than most pigment particles. The flatting agents as used herein are distinguished from soluble dyes in that they are not coloring materials and are not soluble in the coating vehicle.

The flatting agents are present in the coating composition of this invention in the form of relatively fine particles having an average particle size between about 1 and 15 microns. In the case of silica aerogels and silicaorganic liquid gels best results are obtained when the average particle size of the aerogel or gel particle is between about 2 and 8 microns.

A large variety of non-ionic surface active agents are useful in the compositions described herein provided they are soluble in the coating composition vehicle in amounts of at least 0.05% by weight. As examples of suitable non-ionic surface active agents may be mentioned the surface active condensation products of alkyl, cyclo-alkyl, aryl or aryl alkyl mercaptans containing at least 6 carbon atoms and preferably not more than 20 carbon atoms, and an alkylene oxide such as ethylene oxide, propylene oxide, butylene oxide and the like. As examples of mercaptans which are useful in preparing such condensation products may be mentioned alkyl mercaptans such as hexyl, octyl, dodecyl, tertiary dodecyl, octodecyl mercaptans and the like; cyclo-alkyl mercaptans such as cyclohexyl mercaptan, methyl cyclohexyl mercaptan and the like; aryl mercaptans such as thiophenol, thionaphthol and the like; and aryl alkyl mercaptans such as benzyl mercaptan and the like. The amount of alkylene oxide used in preparing the condensation products may be varied considerably, but should at least be sufficient to produce a surface active product. In general, the condensation products prepared by condensing from about 4 to 20 molecular proportions of alkylene-oxide with 1 molecular proportion of the mercaptan are suitable for use in the compositions of this invention while those prepared from 7 to 16 mols of alkylene oxide and 1 mol of mercaptan are preferred.

Best results have been obtained with condensation products of alkyl mercaptans, and particularly tertiary alkyl mercaptans, containing from 8 to 16 carbon atoms,

and ethylene oxide, especially those products containing from 7 to 15 ethenoxy residues per mol of mercaptan. Such condensation products are believed to have the following structural formula:

where R is the alkyl radical and x is a positive integer between 5 and 13. These condensation products are preferred for use in the compositions described herein.

Other non-ionic surface active agents which are also useful in the compositions of this invention include the surface active condensation products of tall oil, rosin oil or rosin acids and alkylene oxides such as ethylene 0xide, propylene oxide and butylene oxide. In general, suitable products are obtained condensing from about 50 to 250 parts of the alkylene oxide with parts of the tall oil, rosin oil or rosin acid, although the products prepared by condensing from 100 to parts of the alkylene oxide with 100 parts of the oil or acid are preferred. Tall oils generally contain between about 30 and 50% by weight of rosin acids including abietic acid and about 60 to 40% by weight of unsaturated acid including linoleic and oleic acids. The condensation products described immediately above are believed to have the following structural formula when ethylene oxide is the alkylene oxide:

RC O(CHB)T '(OCH2'CH1)z'0-CH2CHZOH where R is the carbon and hydrogen residue of the tall oil, rosin oil or rosin acid and x is a positive integer, preferably between about 4 and 16. Of the above condensation products, the products prepared from tall oil and ethylene oxide are preferred.

Non-ionic surface active agents prepared by condensing alkylene oxides such as ethylene oxide with alkyl amides containing at least 7 and preferably from 10 to 20 carbon atoms are also suitable for use in the compositions of this invention. As examples of suitable amides which are used in preparing such agents may be mentioned octanamide, decanamide, amylamide, hexadecanamide, stearamide and the'like. The alkylene' oxide should be used in amounts sufiicient to make the condensation product surface active. In general, products prepared by condensing from about 5 to 20 molecular proportions of the alkyleneoxide with 1 molecular proportion of the amide are suitable. The products prepared by using ethylene oxide as the alkylene oxide are preferred. Best results have been obtained by usingthe condensation products of 1 molecular proportion. of laurylamide or dodecanamide and 7 to 16 molecular proportions of ethylene oxide. The products obtained by using ethylene oxide are believed to have the'structural formula:

where R is an alkyl group and x is a positive integer, preferably between 5 and 13.

The non-ionic surface active agents are generally prepared by methods known in the art,'for example, by re- I acting the alkylene oxide and the mercaptan, tall oil or fatty acid, or fatty acid amide such as the lauryl amide at elevated temperatures, that is, temperatures above 90 C., and preferably between 100 and 200 C., in the presence of a small amount, say from about 0.1'to 3% on the weight of the mercaptan or other condensing compound, of an alkaline catalyst such as sodium hydroxide or carbonate, ammonia, or sodium or potassium ethylate;

The non-ionic surface active agents described herein serve the function of fiocculating the fiatting agentparticles thereby substantially preventing hard settling, that is, the formation of hard, gummy cakes of fiatting agent particles. This flocculating effect of the non-ionic surface active agents in a coating composition vehicle and particularly a drying oil varnish vehicle is especially noticeable in the case of silica aerogel particles which normally form a hard, gummy cake in the absence of such non-ionic agents.

The exact mechanism by which the non-ionic surface active agents prevent hard settling of the silica fiatting agents is not understood, but it is believed that the nonionic agent coats the particles of the silica fiatting agent, and particularly the silica aerogels, preferentially and deactivates the surface of the particle thereby markedly reducing the attraction between the particles of fiatting agent and the resinous substances in the coating" composition and also between the particles of fiatting agent; In any event, hard settling is substantially prevented and the particles of fiatting agent are in a flocculated condition. Thus, although the particles of fiatting. agent may and oftentimes do settle to some extent they form a voluminous, soft layer in the coating composition and this deposit is readily dispersed by simple agitation.

The compositions of this invention are prepared, in general, by dispersing the silica fiatting agent in the coating composition in the presence of the nonionicv surface active agent. This may be accomplished in a variety of ways depending to some extent on the particular coating composition used. For example, when the silica flatting agent is to be incorporated in a vinyl lacquer such. as-a vinyl chloride-vinyl acetate copolymer lacquer which; is to be used for coating fabrics itis possible to dispersethe fiatting agent by stirring it into the lacquer in the presence of the non-ionic surface active agent. With wood lac quers and drying oil varnishes where the smoothness of the coating is of importance, it is preferred to grind the silica fiatting agent and the lacquer or-drying oil varnishin the presence of the non-ionic agent untilthe dispersionis smooth and the flattingagentis-in a flocculated condition when the composition is allowed to stand. when smoothness of the coating is of primary interest,.it is preferable to grind the mixture in a. pebble mill until the fiatting agent has the desired particle size;

In the case of lacquers and=dryingoil varnishesit is preferred to grind the coating compositio'n and-'- the flatting agent in the presence of the non-ionic agent and then add at least one and preferably 2 or more increments of the lacquer or varnish, as the case may be, tobuildup the solids content of the original grind. This'enables the preparation of fairly concentrated coating compositions. In the case of lacquers, that is, a solution of} a-film-form* ing material in a solvent and which does not require oxidation to produce a useful film, it is not necessary to grind the mixture after the increments of lacquer have been added to the original grind. However, in the'case of drying oil varnishes best results have been obtained bygrinding the composition after eachaddition of varnish to the original grind and, accordingly, this procedure is preferred with drying oil varnishes.

The grinding, when such a technique is employed, may be carried out in a pebble mill, steel ball mill, two roller mill or the like. Other forms of grinding apparatus may be used as will be apparent to'those skilled'in the art. Best results have been obtained by grinding the ingredients in a ball mill and accordingly such means are pre ferred in preparing the compositions of this invention.

The proportion of ingredients used may be varied considerably depending upon the type of finishdesired, that is, whether it is to be a fiat or semi-gloss 'finish, andthe particular coating composition and silica fiatting agent employed in the composition. The coating composition may be used as it is prepared and may comprise, for example, from about 20 to 60% by weight solids'in such instances. On the otherhand, the coating composition may be thinned down with a miscible, relatively nonviscous thinner such'as a medium boiling aromatic liquid either prior to, during or after the addition of the fiatting agent and non-ionic surface active agent. In most instances, it is preferred to thin the coating composition to a solids content of about 15 to 35% by weight duringthe initial grinding operation and at the time the fiatting agent and non-ionic surface active agent are added to the coating compositionand then add increments of the coating composition to the resulting grind to buildup the solids content of the composition to about 20 to 50% by Weight. For best results, it is preferred to grind the'ini'tial mixture and the mixture obtained by the addition of coating composition vehicle until the grind is smooth.

The amount of silica fiatting agent added depends primarily upon the type of finish desired and the efli'ciency of the fiatting agent. When silica aerogels or silica-organic liquid gels of the .type previously described herein are used, it is possible to use smaller amounts than would normally be used in the case'of. other flattingagents to obtain the same reduction in gloss. Ingeneral, the fiat ting agent is used in amounts suflicient to'decrease the gloss of the coating, but insufiicient to materially reduce the clarity, transparency and strength of the coating film. Satisfactory semi-gloss results are obtained'especially in the case of silica aerogels or the silica-organicliquid. gels by using from 1 to 5% of fiatting agent. solids based on the coating composition solids in. the finalcomposition.- In some cases even less than 1% of silica aerogel solids may be used if only a slightly dulled: film is desired.- Com! pletely fiatted coatings may be obtainedvbyusing up to 30% on the coating composition solids of a silica aerogel or a silica-organic liquid gel without detractingv appreciably from the clarity, transparency or strength of the coating film. However, with other silica fiatting agents smaller amounts must be used whenno appreciable loss in coating film strength can be tolerated. When silica aerogels or silica-organic liquid gels are used it is pre'-' ferred to employ from 5 to 15% of such: materialson the coating composition solids in'the final coating mixture for most purposes.

The' amount of non-ionic surface activeagent usedjis dependent primarily onthe concentration of fiatting agent used and is also dependentontheparticular fiatting: agent used. Thus, it is possible to use-smaller amounts of the non-ionic agent when relatively small amounts of the flatting agent are employed. Moreover, it is possible to use smaller amounts of the non-ionic agent when the fiatting agent is an ordinary silica gel than in the case of silica aerogels. Satisfactory results are obtained, in general, by using from about 1 to 30% of the non-ionic agent based on the weight of the flatting agent. However, it is to be understood that even smaller amounts of the non-ionic agent may be used in some instances while larger amounts may be used if the non-ionic agent is highly soluble and the properties of the varnish film are not materially altered. In most cases the use of from 4 to 20% of the non-ionic agent on the weight of the flattlng agent produces the best results and such amounts are accordingly preferred.

In carrying out the preparation of the flatted or semigloss coating compositions the time of grinding may be varied considerably depending upon the grinding medium or vehicle and the type of grinding means and procedure used. In general, the total grinding time varies between about 5 and 16 hours in a pebble or ball mill, of which the initial grinding period is from about 4 to hours and the subsequent grinding periods are from about 1 to 6 hours. It will be understood, of course, that for certain types of finishes the coating composition-fiatting agent mixture may be under ground, that is, ground for relatively short periods of time and, on the other hand, the mixture may be over-ground, that is, ground for long periods of time especially when smoothness is desired. In the latter case the improved smoothness of the coating is obtained with some loss in flatting efficiency. For silica aerogels a total grinding period of from 6 to 16 hours in a pebble mill is usually sufiicient and generally gives the best result. In carrying out the grinding of silica aerogels and silica-organic liquid gels in a varnish vehicle, it is preferred to initially grind the flatting agent in the thinned varnish vehicle for a period of 6 to 12 hours in a pebble mill and then grind the mixture for periods of minutes to 90 minutes after the addition of more varnish to the mixture. The subsequent grinding operations are preferably carried out so that the total subsequent grinding time is more than 30 minutes and less than 200 minutes.

A further understanding of the compositions and methods of this invention will be obtained from the following specific examples which are intended to illustrate this invention but not to limit the scope of the invention, parts and percentages being by weight unless otherwise specified.

Example I A linseed oil modified glycerine-phthalic anhydride alkyd resin varnish of medium oil length and containing 38% solids and having an acid value of was used as the drying oil varnish.

Fifty-nine parts of the above varnish thinned with 205 parts of medium boiling naphthenic hydrocarbon solvent together with parts of finely divided silica aerogel having a dry bulk density of 6 pounds per cubic foot, and 6 parts of the soluble condensation product of 2. parts of tertiary dodecyl mercaptan and 4.56 parts of ethylene oxide were ground in a one-quart pebble mill at R. P. M. for a period of about 14 hours to form a mill base. One hundred parts of the varnish were added to the mixture in the pebble mill and the resulting mixture was ground for one hours at 60 R. P. M. Two hundred and forty-one parts of the varnish were added to the pebble mill and the resulting mixture was ground for a period of one hour at 60 R. P. M. to provide a fiat varnish.

The silica aerogel in the varnish remained in a flocculent condition giving a varnish which retained its excellent appearance and properties over an extended period of time. The aerogel in the varnish did not settle to form a hard cake, but, on the contrary, formed a voluminous soft layer which was readily dispersed by simple stirring.

A flatted varnish prepared in the same manner but '8 without the use of the mercaptan-ethylene oxide condensation product settled rapidly to form a low volume deposit which deteriorated into a hard, gummy mass within a period of 2 weeks.

Example 11 A phenolic type varnish was first prepared as follows:

One hundred pounds of a pure phenolic resin, prepared by heating para tertiary amyl phenol with formaldehyde under alkaline conditions, and 12.5 gallons of alkali refined linseed oil were heated to a temperature of 565 F. within a period of 40 minutes and then held at that temperature for a period of minutes. Twelve and fivetenths gallons of tung oil were then added and the batch was heated to a temperature of 525 F. and held at that temperature until it had a viscosity of E. The batch was then cooled and thinned with mineral spirits until it contained 50% solids. Sufiicient amounts of cobalt and lead naphthenate were then added to the thinned batch to, provide 0.03% cobalt and 0.3% lead, respectively, as metal based on the oil in the batch.

Two hundred and fifty-eight parts of the above described varnish thinned with 50 parts of a medium boiling naphthenie hydrocarbon solvent, 13 parts of silica aerogel and 2.0 parts of the condensation product of 1 part of tertiary dodecyl mercaptan and 2.28 parts of ethylene oxide were ground to smoothness in a one-quart pebble mill, which required about 11 hours. A fiat varnish was thus obtained in which the silica aerogel was finely flocculated. After aging for 6 months the silica aerogel particles in the varnish were easily redispersed by simple stirring and did not form a hard, gummy cake as in the case of a similar varnish prepared without the mercaptanethylene oxide condensation product.

Example III A varnish was prepared by first heating 20 gallons of an alkali refined linseed oil and pounds of a phenol modified copal resin having a melting point of 167 to 172 C. and an acid value of 20 to 25 to a temperature of 585 F., after which the mixture was held at 585 F. for a period of 40 minutes to body the mixture. Five gallons of bodied linseed oil were then added and the resulting mixture was thinned with mineral spirits until it contained 50% non-volatile matter. Sutficient amounts of cobalt and lead naphthenate were then added to provide 0.03% cobalt and 0.3% lead, respectively, as metal based on the oil in the varnish.

A silica aerogel flatted varnish was produced from the above varnish using the procedure described in the second paragraph of Example II. The silica aerogel in the flatted varnish remained in a flocculent condition and did not hard settle. Varnish films formed from the flatted varnish had excellent clarity and transparency and were substantially flat in appearance.

Example I V A linseed oil-ester gum varnish having an oil length of 12.5 and an acid value of 5 and containing 55% solids was used as the drying oil varnish.

Two hundred and twenty-five parts of the above varnish, 56 parts of turpentine, 17 parts of silica aerogel having a dry bulk density of 6 pounds per cubic foot and 2 parts of the condensation product of 1 part of tertiary dodecyl mercaptan and 2.28 parts of ethylene oxide were ground in a pebble mill for a period of 8 hours. Eighty-four parts of the clear varnish were added to the mixture in the pebble mill and the liquid mass was ground in the pebble mill for three hours. The resulting varnish contained the aerogel in flocculated form and provided dry varnish films having a gloss of 50 as measured by a Gardner 60 Glossmeter. After aging for long periods of time, that is, at least 12 months, the varnish appeared to be stable and had substantially the same appearance as the freshly flatted varnish. Varnish films cast from the aged varnish were substantially as smooth, flat and saga-1a 9 free of agglomerates as the films cast from the freshly prepared varnish. I

A flatted varnish prepared in the same manner but without the use of the mercaptan-ethylene oxide condensation product had settled within two weeks to form a hard, gummy, non-redispersible cake.

The following example illustrates the use of a non-ionic surface active agent in a silica aerogel flatted commercial cellulosic wood lacquer to prevent hard settling of the silica aerogel fiatting agent.

Example V I A nitrocellulose lacquer grind was first prepared by grinding the ingredients tabulated below in the proportions shown in a pebble mill for a period of 6 hours.

Parts Butyl acetate 26.3 Butyl alcohol 20.6 Toluol i 30.5 Processed castor oil 5.1 Denatured alcohol 2.9 A.; second dry nitrocellulose 5.4

Silica aerogel (dry bulk density 6 pounds per cubic foot) 9.2 Condensation product of 1 part of tertiary dodecyl mercaptan and 2.28 parts ethylene oxide 0.7

Ten parts of the above lacquer grind: were added to 90 parts of a wood lacquer having the following composition:

The composition obtained as described above formed coatings having a gloss of about 50' on a Gardner 60 Glossmeter. The aerogel in the lacquer settled asa soft voluminous layer which remained ina fiocculated condition after storing for 7 months and was readily dispersed by simple stirring. The silica aerogel in'a. duplicate lacquer which did not contain the mercap-tan-ethylene oxide condensation product settled to form a diflicultly dispersible cake when stored for 7 months.

The procedure described 'in'this example is also applicable to the flatting of cellulose acetate, cellulose acetobutyrate and ethyl cellulose lacquers for the prevention of hard settling of silica aerogel particles.

Example VI Flatted compositions were prepared in the same manner as those described in the preceding examples with the exception that the condensation product of 1 part of tall oil and 1.4 parts of ethylene oxide was usedinstead of the mercaptan-ethylene oxide condensation product. Similar results were obtained in that the silica aerogelflatting agent remained in a flocculent condition in the r flatted compositions and did not hardsettle as inthe case where the condensation product is omitted.

Example VII 1 0 through V in' that the silica aerogel remained in a fiocculentcondition in the coating composition and did'not hard settle.

Various changes and modifications may be made in-- the compositions and methods described herein, as will be apparent to those skilled in the art to which this invention appertains, without departingfrom the spirit and intent of the present invention. Accordingly, it is to be understood thatthe present invention is to be limited only by the scope of the appended claims.

Whatis claimed is:

1;. A composition of matter consisting essentially of a drying oil. resin varnish containing an organic solvent and from about 20m by weight of solids, from 5 to 15% on the weight of solids in said varnish of a silica aerogel and from 4 to 20% on the weight of said aerogel of a surface active condensation product of 7 to -15 molecular proportions of ethylene oxide with- 1 molecular proportion of tertiary dodecyl mercaptan,. said condensation product being soluble in said varnish in amounts of at least0.05% by weight.

2. A composition of matter consisting essentially of a drying oil resin varnish containing an organic'solvent and from about 20 to 60% by weight of solids in which is incorporated a silica aerogel in an amount suificient toreduce the gloss of films prepared from said varnish and from 1 to 30%, on the weight of said aerogel, of a non-ionic surface active agent, said surface active agent being a surface active condensation product of 7 to 15 mols of ethylene oxide and 1 mol of a tertiary alkyl mercaptan containing from 8 to 16 carbon atoms, said condensation product being soluble in said varnish in amounts of at least 0.05% by weight, said silica aerogel being present in said varnish ina fiocculent. condition and in the form of'a voluminous, soft layer.

3. A process of preparing flatted and semi-gloss drying oil resin varnishes which comprises grinding a mixture of a. silica aerogel and a drying oil resin varnish containing an organic solvent and from about 15 to 35% by weight of solids in a pebble millfin the presence of from about 4 to 20%,v on the weight of the aerogel, of a non-ionic surface active condensation product of 7 to 1'5 mols'of ethylene oxide and 1 mol of a tertiary alkyl mercaptan containingfrom 8 to 16 carbon atoms, said condensation product beingsoluble in said varnish in amounts of at least*0.05 by weight, until the aerogel is fiocculated in said varnish and then .adding at least one additional increment of a drying oil resin varnish containing the same ingredients as the initial varnishto said mixture and grinding the mixture in a-pebble mill until the aerogel in said varnish remains in a fiocculated condition when the varnish is allowedto stand, the amount of varnish thus added being sufiicient. toprovide a composition'which contains from lib ' aboutv 20 to 50% by weight of solids, the amount of aerogel employed being suflicient to provide from about 5 to 15% of aerogel, based on the total varnish solids.

' 4. A process of preparing flatted and semi-gloss drying oil resin varnishes which comprises grinding a mixture of a silica aerogel and a drying oil resin varnishcontaining an organic solvent and from about 15 to 35% by weight of solids in a pebble mill in the presence of from about 4 to 20%, on the weight of the aerogel, of a' non-ionic surface active condensation product of 7 to 15 molecular proportions of ethylene oxide and 1 molecular'proportion of tertiary dodecyl. mercaptan, said condensation product being soluble in said varnish in amounts of at least 0.05% by weight, until the aerogel is fiocculated in said varnish and then adding at least one additional increment of a drying oil resin varnish containing the same ingredients as the initial varnish to said mixture and grinding the mixture in a pebble mill until the aerogel in said varnish .remains in a fiocculated condition when the varnish is allowed to stand, the amount 11 of varnish thus added being suflicient to provide a composition which contains from about 20 to 50% by weight of solids, the amount of aerogel employed being suificient to provide from about to of aerogel based on the total varnish solids.

5. A composition of matter consisting essentially of a drying oil-resin varnish containing an organic solvent and from to 60% by Weight of solids, from 1 to 30% on the Weight of solids in said varnish of a silica aerogel and from 1 to 30% on the weight of said aerogel of a surface active condensation product of 7 to 15 molecular proportions of ethylene oxide with 1 molecular proportion of tertiary dodecyl mercaptan, said condensation product being soluble in said varnish in amounts of at least 0.05 by Weight.

6. A composition of matter consisting essentially of a drying oil-resin varnish containing an organic solvent and from 20 to 60% by Weight of solids in which is incorporated a silica flatting agent in an amount sufllcient to reduce the gloss of films prepared from said varnish and from 1 to 30% on the weight of said flatting agent, of a non-ionic surface active agent selected from the group consisting of (1) a surface active condensation product of 4 to 20 molecular proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of a mercaptan selected from the group consisting of alkyl mercaptans, cycle-alkyl mercaptans, aryl mercaptans and aryl alkyl mercaptans, all of which mercaptans contain at least 6 carbon atoms, (2) a surface active condensation product of 50 to 350 parts of an alkylene oxide having from 2 to 4 carbon atoms and 100 parts of a substance selected from the group consisting of tall oil, rosin oil, and rosin acid and (3) a surface active condensation product of 5 to 20 molecular proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of an alkyl amide containing at least 7 carbon atoms, said surface active agent being soluble in said varnish in amounts of at least 0.05% by weight, said silica fiatting agent being present in said varnish in a fiocculent condition and in the form of a voluminous, soft layer.

7. A composition of matter consisting essentially of a drying oil-resin varnish containing an organic solvent and from 20 to 60% by weight of solids in which is incorporated a silica aerogel in an amount sutficient to reduce the gloss of films prepared from said varnish and from 1 to 30%, on the weight of said aerogel, of a non-ionic surface active agent selected from the group consisting of (1) a surface active condensation product of 4 to 20 molecular proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of a mercaptan selected from the group consisting of alkyl mercaptans, cycloalkyl mercaptans, aryl mercaptans and aryl alkyl mercaptans, all of which mercaptans contain at least 6 carbon atoms, (2) a surface active condensation product of 50 to 250 parts of an alkylene oxide having from 2 to 4 carbon atoms and 100 parts of a substance selected from the group consisting of tall oil, rosin oil, and rosin acid and (3) a surface active condensation product of 5 to 20 molecular proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of an alkyl amide containing at least 7 carbon atoms, said surface active agent being soluble in said varnish in amounts of at least 0.05% by Weight, said aerogel being present in said varnish in a fiocculent condition and in the form of a voluminous, soft layer.

8. A composition of matter consisting essentially of a drying oil-resin varnish containing an organic solvent and from about 20 to 60% by weight of solids, from 1 to 30%, on the weight of solids of said varnish, of a silica aerogel and from 1 to 30%, on the Weight of said aerogel, of a non-ionic surface active agent selected from the group consisting of (1) a surface active condensation product of 4 to 20 molecular pro portions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of a mercaptan selected from the group consisting of alkyl mercaptans, cycle-alkyl mercaptans, aryl mercaptans and aryl alkyl mercaptans, all of which mercaptans contain at least 6 carbon atoms, (2) a surface active condensation product of 50 to 250 parts of an alkylene oxide having from 2 to 4 carbon atoms and parts of a substance selected from the group consisting of tall oil, rosin oil, and rosin acid and (3) a surface active condensation product of 5 to 20 molecular proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of an alkyl amide containing at least 7 carbon atoms, said surface active agent being soluble in said varnish in amounts of at least 0.05% by Weight, said aerogel being present in said varnish in a flocculent condition and in the form of a voluminous, soft layer.

9. A composition of matter consisting essentially of a drying oil-resin varnish containing an organic solvent and from 20 to 60% by weight of solids in which is incorporated a silica flatting agent in an amount suflicient to reduce the glOSS of films prepared from said varnish and from 1 to 30%, on the weight of said flatting agent, of a non-ionic surface active agent consisting of a surface active condensation product of 7 to 15 mols of ethylene oxide and 1 mol of an alkyl mercaptan containing from 8 to 16 carbon atoms, said surface active agent being soluble in said varnish in amounts of at least 0.05% by weight, said silica flatting agent being present in said varnish in a flocculent condition and in the form of a voluminous, soft layer.

10. A process of preparing flatted and semi-gloss drying oil-resin varnishes which comprises grinding a mixture of a silica aerogel and a drying oil-resin varnish containing an organic solvent and from about 15 to 35% by weight of solids in a pebble mill in the presence of from about 4 to 20%, on the weight of the aerogel, of a non-ionic surface active agent consisting of a surface active condensation product of 7 to 15 mols of ethylene oxide and 1 mol of an alkyl mercaptan containing from 8 to 16 carbon atoms, said condensation product being soluble in the varnish in amounts of at least 0.05% by weight, until said aerogel is flocculated in said varnish and then adding at least one additional increment of a drying oil-resin varnish containing the same ingredients as the initial varnish to said mixture and grinding the mixture in a pebble mill until said aerogel in said varnish remains in a flocculated condition when the varnish is allowed to stand, the amount of varnish thus added being suificient to provide a composition which contains from about 20 to 50% by weight of solids, the amount of said aerogel employed being sufficient to provide from 1 to 30% of aerogel based on the total varnish solids.

11. A composition of matter consisting essentially of a drying oil-resin varnish in which is incorporated a silica fiatting agent in an amount sufficient to reduce the gloss of films prepared from said varnish and from 1 to 30%, on the weight of said flatting agent, of a non-ionic surface active agent selected from the group consisting of 1) a surface active condensation product of 4 to 20 molecular proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of a mercaptan selected from the group consisting of alkyl mercaptans, cyclo-alkyl mercaptans, aryl mercaptans and aryl alkyl mercaptans, all of which mercaptans contain at least 6 carbon atoms, (2) a surface active condensation product of 50 to 250 parts of an alkylene oxide having from 2 to 4 carbon atoms and 100 parts of a substance selected from the group consisting of tall oil, rosin oil, and rosin acid and (3) a surface active condensation product of 5 to 20 molecular proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of an alkyl amide containing at least 7 carbon atoms, said ass sts 1'3 surface, active agents being soluble in said varnish amounts of at' least'0.05'% by weight, said silica flatting agent being present: in saidvarnishin a flocculentcondition and in the form-of-a voluminous, soft layer:

12. A compositionj of. mattenconsisting essentially of a drying oli-resin' varnish 'in'whichis incorporated a silicaaerogel in an amount 'sutficient' toweduce the gloss of films prepared from said varnish and from 1 to 30%, on the weight of said aerogel, of a non-ionic surface active agent selected from the group consisting of (l) a surface active condensation product of 4 to 20 molecular proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of a mercaptan selected from the group consisting of alkyl mercaptans, cycloalkyl mercaptans, aryl mercaptans and aryl alkyl mercaptans, all of which mercaptans contain at least 6 carbon atoms, (2) a surface active condensation product of 50 to 250 parts of an alkylene oxide having from 2 to 4 carbon atoms and 100 parts of a substance selected from the group consisting of tall oil, rosin oil, and rosin acid and (3) a surface active condensation product of 5 to 20 molecular proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of an alkyl amide containing at least 7 carbon atoms, said surface active agent being soluble in said varnish in amounts of at least 0.05% by weight, said aerogel being present in said varnish in a fiocculent condition and in the form of a voluminous, soft layer.

13. A process of preparing fiatted and semi-gloss compositions which comprises grinding a silica flatting agent in a drying oil-resin varnish in the presence of from 1 to 30%, on the weight of said silica fiatting agent, of a non-ionic surface active agent until said flatting agent remains in a fiocculent condition when said varnish is allowed to stand, said surface active agent being soluble in said varnish in amounts of at least 0.05 by weight and consisting of a surface active condensation product selected from the group consisting of (l) a surface active condensation product of 4 to 20 molecular 40 proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of a mercaptan selected from the group consisting of alkyl mercaptans, cyclo-alkyl mercaptans, aryl mercaptans and aryl alkyl mercaptans, all of which mercaptans contain at least 6 carbon atoms, (2) a surface active condensation product of 50 to 250 parts of an alkylene oxide having from 2 to 4 carbon atoms and 100 parts of a substance selected from the group consisting of tall oil, rosin oil, and rosin acid and (3) a surface active condensation product of 5 to 20 molecular proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of an alkyl amide containing at least 7 carbon atoms, said flatting agent being employed in an amount sufiicient to reduce the gloss of films prepared from said varnish.

14. A process of preparing fiatted and semi-gloss compositions which comprises grinding a mixture of a drying oil-resin varnish and a silica aerogel in the presence of from 1 to 30%, on the weight of said aerogel, of a nonionic surface active agent until said silica aerogel remains in a fiocculent condition when said varnish is allowed to stand, said surface active agent being soluble in said varnish in amounts of at least 0.05 by weight and consisting of a surface active condensation product selected from the group consisting of (1) a surface active condensation product of 4 to 20 molecular proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of a mercaptan selected from the group consisting of alkyl mercaptans, cyclo-alkyl mercaptans, aryl mercaptans and aryl alkyl mercaptans, all of which mercaptans contain at least 6 carbon atoms, (2) a surface active condensation product of 50 to 250 parts of an alkylene oxide having from 2 to 4 carbon atoms and 100 parts of a substance selected from the group consisting of tall oil, rosinoil; androsin acid and 3) asurfaceactive condensation pro duct o', fi5 to- 20' molecular proportions of, an alkyleneoxide-having from 2' to 4 carbonatoms and 1 molecular proportion of an alkyl amide containing at least 7 carbon,aterns, said silica aerogel being employed in an amount sufficierit to'reduc' the gloss of films prepared from said varnish 1 15, A; process of preparing; fiatted andsemi-gloss drying oil-resin varnishes which comprises grinding a mixture of a drying oil-resin varnish containing an organic solvent and from 15 to 35% by weight of solids and from 1 to 30%, on the weight of varnish solids in the final composition, of a silica flatting agent in the presence of from 1 to 30%, on the weight of said flatting agent, of a nonionic surface active agent,'said mixture being ground at least until the flattening agent is flocculated in said varnish, adding at least one additional increment of a drying oilresin varnish containing the same ingredients as the initial varnish and grinding said mixture until said flatting agent remains in a fiocculent condition when the varnish is allowed to stand, the amount of varnish thus added being sufiicient to provide a composition which contains from about 20 to 50% by weight of varnish solids, said surface active agent being soluble in said varnish in amounts of at least 0.05 by weight and consisting of a surface active condensation product selected from the group consisting of (1) a surface active condensation product of 4 to 20 molecular proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of a mercaptan selected from the group consisting of alkyl mercaptans, cycloalkyl mercaptans, aryl mercaptans and aryl alkyl mercaptans, all of which mercaptans contain at least 6 carbon atoms, (2) a surface active condensation product of 50 to 250 parts of an alkylene oxide having from 2 to 4 carbon atoms and parts of a substance selected from the group consisting of tall oil, rosin oil, and rosin acid and (3) a surface active condensation product of 5 to 20 molecular proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of an alkyl amide containing at least 7 carbon atoms.

16. A process of preparing fiatted and semi-gloss drying oil-resin varnishes which comprises grinding a mixture of a drying oil-resin varnish containing an organic solvent and from about 15 to 35% by weight of solids and a silica aerogel in a pebble mill in the presence of from about 4 to 20%, on the weight of said aerogel, of a non-ionic surface active agent until said aerogel is fiocculated in said varnish, adding at least one additional increment of a drying oil-resin varnish containing the same ingredients as the initial varnish to said mixture and grinding the mixture in a pebble mill until said aerogel in said varnish remains in a fiocculent condition when the varnish is allowed to stand, the amount of varnish thus added being suflicient to provide a composition which contains from about 20 to 50% by weight of varnish solids, the amount of aerogel employed being sufficient to provide from about 5 to 15% by weight of aerogel based on the total varnish solids, said surface active agent being soluble in said varnish in amounts of at least 0.05 by weight and consisting of a surface active condensation product selected from the group consisting of l) a surface active condensation product of 4 to 20 molecular proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of a mercaptan selected from the group consisting of alkyl mercaptans, cycloalkyl mercaptans, aryl mercaptans and aryl alkyl mercaptans, all of which mercaptans contain at least 6 carbon atoms, (2) a surface active condensation product of 50 to 250 parts of an alkylene oxide having from 2 to 4 carbon atoms and 100 parts of a substance selected from the group consisting of tall oil, rosin oil, and rosin acid and (3) a surface active condensation product of 5 to 20 molecular proportions of an alkylene oxide having from 2 to 4 carbon atoms and 1 molecular proportion of an alkyl 2,129,709 Schuette et al. Sept. 13, 1938 amide containing at least 7 carbon atoms. 2,291,293 Curtis July 28, 1942 17. A process according to claim 15, but further char- 2,417,344 Barrett Mar. 11, 1947 acterized in that the fiatting agent is a silica aerogel. 2,522,446 Harris P 1950 References Cited in the file of this patent UNITED STATES PATENTS Schoeller et a1. Aug. 21, 1934 OTHER REFERENCES American Ink Maker of April 1943, pages 19-23.. 

3. A PROCESS OF PREPARING FLATTED AND SEMI-GLOSS DRYING OIL RESIN VARNISHES WHICH COMPRISES GRINDING A MIXTURE AN ORGANIC SOLVENT AND FROM ABOUT 15 TO 35% BY WEIGHT OF SOLIDS IN A PEBBLE MILL IN THE PRESENCE OF FROM ABOUT 4 TO 20%, ON THE WEIGHT OF THE AEROGEL, OF A NON-IONIC SURFACE ACTIVE CONDENSATION PRODUCT OF 7 TO 15 MOLS OF ETHYLENE OXIDE AND 1 MOL OF A TERTIARY ALKYL MERCAPATAN CONTAINING FROM 8 TO 16 CARBON ATOMS, SAID CONDENSATION PRODUCT BEING SOLUBLE IN SAID VARNISH IN AMOUNTS OF AT LEAST 0.05% BY WEIGHT, UNTIL THE AEROGEL IS FLOCCULATED IN SAID VARNISH AND THEN ADDING AT LEAST ONE ADDITIONAL INCREMENT OF A DRYING OIL RESIN VARNISH CONTAINING THE SAME INGREDIENTS AS THE INITIAL VARNISH TO SAID MIXTURE AND GRINDING THE MIXTURE IN A PEBBLE MILL UNTIL THE AEROGEL IN SAID VARNISH REMAINS IN A FLOCCULATED CONDITIONS WHEN THE VARNISH IS ALLOWED TO STAND, THE AMOUNT OF VARNISH THUS ADDED BEING SUFFICIENT TO PROVIDE A COMPOSITION WHICH CONTAINS FROM ABOUT 20 TO 50% BY WEIGHT OF SOLIDS, THE AMOUNT OF AEROGEL EMPLOYED BEING SUFFICIENT TO PROVIDE FROM ABOUT 5 TO 15% OF AEROGEL, BASED ON THE TOATL VARNISH SOLIDS. 